Potential Role for Urine Polymerase Chain Reaction in the Diagnosis of Whipple's Disease.

BACKGROUND: Whipple's disease (WD) is a rare infection with Tropheryma whipplei that is fatal if untreated. Diagnosis is challenging and currently based on invasive sampling. In a case of WD diagnosed from a kidney biopsy, we observed morphologically-intact bacteria within the glomerular capsular space and tubular lumens. This raised the questions of whether renal filtration of bacteria is common in WD and whether polymerase chain reaction (PCR) testing of urine might serve as a diagnostic test for WD. METHODS: We prospectively investigated urine samples of 12 newly-diagnosed and 31 treated WD patients by PCR. As controls, we investigated samples from 110 healthy volunteers and patients with excluded WD or acute gastroenteritis. RESULTS: Out of 12 urine samples from independent, therapy-naive WD patients, 9 were positive for T. whipplei PCR. In 3 patients, fluorescence in situ hybridization visualized T. whipplei in urine. All control samples were negative, including those of 11 healthy carriers with T. whipplei-positive stool samples. In our study, the detection of T. whipplei in the urine of untreated patients correlated in all cases with WD. CONCLUSIONS: T. whipplei is detectable by PCR in the urine of the majority of therapy-naive WD patients. With a low prevalence but far-reaching consequences upon diagnosis, invasive sampling for WD is mandatory and must be based on a strong suspicion. Urine testing could prevent patients from being undiagnosed for years. Urine may serve as a novel, easy-to-obtain specimen for guiding the initial diagnosis of WD, in particular in patients with extra-intestinal WD.

Organisation of lymphocytic infiltrates in ANCA-associated glomerulonephritis.

AIMS: Renal involvement in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis contributes to significant morbidity and mortality in patients. In chronic inflammation, B cells are recruited to the inflamed tissue and organised lymphoid structures have been described in several autoimmune diseases. The aim of this study was to correlate the lymphoid organisation in renal biopsies with renal outcome in ANCA-associated glomerulonephritis (GN). METHODS AND RESULTS: We investigated 112 renal biopsies from patients with newly diagnosed ANCA-associated necrotising GN. We identified four different levels of the intrarenal organisation of lymphocytes: T cells without B cells, scattered B and T cells, clustered lymphocytic infiltrates and nodular compartmentally arranged B and T cell aggregates. Almost half the patients showed clusters of B and T lymphocytes in their biopsies. In 15 of these biopsies, a higher degree of organisation with lymphocytic compartments was detected. Inflammatory cell organisation was associated with renal failure, but not with tubular atrophy and interstitial fibrosis. Patients with organised lymphocytic infiltrates in their biopsy had worse renal function during follow-up and were more likely to develop end stage renal disease. CONCLUSIONS: In the present study, we show that the renal lymphocytic organisation is associated with renal outcome in ANCA-associated GN. The organisation of the lymphocytic infiltrate may be a morphological correlate of a perpetual and exaggerated inflammation in renal ANCA disease. Classifying the lymphocytic infiltrate could help to predict renal outcome, and might therefore be used for individualised adjustments in the intensity and duration of immunosuppressive therapy.